Cam drive gear, looking for explanation/discussion Options

[type47]

I would like to know what the engine builders on this site do about matching the cam drive gear to the crank gear with respect to the backlash of the gear set. I realize that if you would be rebuilding a factory engine (as assembled at the factory) that the gears would be matched as there are either 7 or 9 gears (the -3, -2, ... +2,+3 or -4 to +4 disignations) that are selected from to match the crank drive gear but my question is what do the builders that don't have the gears matched (as in selecting components that were not in the same engine like if you had to buy a replacement cam or crankshaft or the crank gear had to be replaced), what attention do you pay to matching the gears like the factory did, or do you even pay attention to that step in the rebuild. I have a cam on the way that will come with a cam gear. Do I need to try to find other gears to measure? I am looking for a discussion on this and measuring the gear backlash and effect on the engine rebuild if there is a mis-match... Thanks in advance.